set_current_path to wrap chdir

chdir is POSIX and will eventually be implemented via
std::filesystem::current_path. Moving this functionality to util helps removing
OS-specific parts from other areas of the code base.

Furthermore make get_temporary_directory return an absolute, resolved path.

Author: tautschnig

src/util/file_util.cpp

@@ -41,6 +41,7 @@ Date: January 2012
 #include <windows.h>
 #include <direct.h>
 #include <util/unicode.h>
+#define chdir _chdir
 #include <util/pragma_pop.def>
 #endif
 
@@ -68,6 +69,15 @@ std::string get_current_working_directory()
   return working_directory;
 }
 
+/// Set working directory.
+/// \param path: New working directory to change to
+void set_current_path(const std::string &path)
+{
+  if(chdir(path.c_str()) != 0)
+    throw system_exceptiont(
+      std::string("chdir failed: ") + std::strerror(errno));
+}
+
 /// deletes all files in 'path' and then the directory itself
 #ifdef _WIN32
 

src/util/file_util.h

@@ -15,8 +15,10 @@ Author: Daniel Kroening, [email protected]
 // C++17 will allow us to use std::filesystem::path::remove_all
 void delete_directory(const std::string &path);
 
-// C++17 will allow us to use std::filesystem::current_path
+// C++17 will allow us to use std::filesystem::current_path (for both get and
+// set)
 std::string get_current_working_directory();
+void set_current_path(const std::string &path);
 
 // C++17 will allow us to use std::filesystem::path(dir).append(file)
 std::string concat_dir_file(const std::string &directory,

src/util/tempdir.cpp

@@ -21,6 +21,7 @@ Author: CM Wintersteiger
 #endif
 
 #include <cstdlib>
+#include <cstring>
 #include <vector>
 
 #if defined(__linux__) || \
@@ -86,7 +87,16 @@ std::string get_temporary_directory(const std::string &name_template)
   const char *td = mkdtemp(t.data());
   if(!td)
     throw system_exceptiont("Failed to create temporary directory");
-  result = std::string(td);
+
+  errno=0;
+  char *wd = realpath(td, nullptr);
+
+  if(wd == nullptr || errno != 0)
+    throw system_exceptiont(
+      std::string("realpath failed: ") + std::strerror(errno));
+
+  result = std::string(wd);
+  free(wd);
 #endif
 
   return result;

unit/util/file_util.cpp

@@ -8,6 +8,7 @@ Author: Daniel Kroening
 
 #include <testing-utils/catch.hpp>
 
+#include <util/exception_utils.h>
 #include <util/file_util.h>
 #include <util/tempdir.h>
 #include <util/unicode.h>
@@ -53,3 +54,16 @@ TEST_CASE("is_directory functionality", "[core][util][file_util]")
   REQUIRE(!is_directory(temp_dir("file")));
   REQUIRE(!is_directory(""));
 }
+
+TEST_CASE("get/set working directory", "[core][util][file_util]")
+{
+  temp_dirt temp_dir("testXXXXXX");
+
+  std::string cwd = get_current_working_directory();
+  REQUIRE(cwd != temp_dir.path);
+  set_current_path(temp_dir.path);
+  REQUIRE(get_current_working_directory() == temp_dir.path);
+  REQUIRE_THROWS_AS(set_current_path("no-such-dir"), system_exceptiont);
+
+  set_current_path(cwd);
+}